The practice and its physicians remain under investigation. Investigators are uncertain which practitioners worked on a regular basis out of the Endoscopy Center of Southern Nevada, where six patients who contracted hepatitis C were treated.

Many of the practice's 14 doctors are active in other corporations and partnerships. Here's a glance at their backgrounds and connections:

DIPAK DESAI

Titles: President, secretary, treasurer, manager, doctor, Endoscopy Center of Southern Nevada

Managing partner, Gastroenterology Center of Nevada

Medical education: Guarat University, India

The basics: Desai, board-certified in gastroenterology and internal medicine, is 65 percent owner of the Endoscopy Center of Southern Nevada. He has served as chief of gastroenterology for University Medical Center and Valley Hospital Medical Center, and he chaired internal medicine at North Vista Hospital. He has taught gastroenterology at the University of Nevada School of Medicine and once sat on the Nevada State Board of Medical Examiners.

Desai is an officer in 17 Nevada-based corporations. He was a managing member of International Healthcare Management Ltd., which sued several doctors and doctors' groups in Hawaii in 2001 in an antitrust action. The company, which sought to provide a new managed-care health plan in the Aloha State, alleged that the defendants fixed fees and terms for care providers, and had planned to organize a doctors' boycott of the group. A federal judge in Hawaii dismissed the lawsuit in 2002.

Until he stepped down about two weeks ago, Desai was also a director of Nevada Mutual Insurance Co., a liability insurer that covers the Endoscopy Center of Southern Nevada. The Nevada State Board of Medical Examiners has records of two settled malpractice cases against Desai: a $40,000 settlement with a patient who alleged that he failed to diagnose colon cancer, and a $12,500 settlement with a patient who alleged he didn't properly diagnose appendicitis.

In 1996, he paid the medical board $2,500 after the board charged him with "advertising the practice of medicine in a false, deceptive or misleading manner" by stating that members of his practice were board-certified in gastroenterology when they were not.

Desai has surrendered his license to practice medicine pending investigations into the Endoscopy Center of Southern Nevada.

ELADIO CARRERA

Title: Doctor, Gastroenterology Center of Nevada

Partner, Endoscopy Center of Southern Nevada

Medical education: University of Texas, Southwestern Medical School, Dallas

Works out of: North Las Vegas, Shadow Lane offices

The basics: Eladio Carrera, who has been in medicine for 28 years, is a doctor within the Gastroenterology Center of Nevada practice and 14 percent owner of the Endoscopy Center of Southern Nevada.

Carrera is general partner in the Carrera Family Limited Partnership and director, president, secretary and treasurer of Eladio S. Carrera, M.D., Professional Corp. Physicians' ranking Web site doctorpricing.com notes that he also works at Valley Hospital Medical Center and Sunrise Hospital and Medical Center.

CLIFFORD CARROL

Titles: Doctor, Gastroenterology Center of Nevada

Manager, Endoscopy Center of Southern Nevada

Medical education: State University of New York at Buffalo

The basics: In addition to serving as an officer at the Endoscopy Center of Southern Nevada, Clifford Carrol is director, president, secretary and treasurer of Clifford Carrol, M.D., Ltd. Carrol also was president and treasurer of a now-dissolved Nevada corporation called Professional Instruments.

He's a diplomat with the American Board of Internal Medicine for Gastroenterology and the American Board of Internal Medicine for Internal Medicine, and he's a fellow of the American College of Physicians. Plus, he's a clinical professor of medicine with the Touro University School of Osteopathic Medicine in San Francisco. Board-certified in gastroenterology and internal medicine, Carrol is a member of the American Society for Gastrointestinal Endoscopy.

VISHVINDER SHARMA

Title: Manager, Spanish Hills Surgical Center

Manager, Endoscopy Center of Southern Nevada

Medical education: Armed Forces Medical College, University of Pune, Maharashtra, India

Works out of: Spanish Hills office

The basics: Vishvinder Sharma is a partner with Dipak Desai in Spanish Hills Surgical Center, an endoscopy clinic in Spring Valley. He's an officer in five other Nevada companies, including V. Sharma, M.D., Ltd.; Centennial Hills Primary Care Ltd.; VBNV LLC; VBCA LLC; an KKS Nevada LLC. Sharma resigned from the Nevada State Board of Health on March 7.

DIPESH BANKER

Title: Doctor, Gastroenterology Center of Nevada

Medical education: Ross University School of Medicine, in Dominica, West Indies

The basics: Dipesh Banker has been a doctor for five years, specializing in internal medicine and gastroenterology.

His biography notes that he graduated with honors from Ross University School of Medicine.

He's a diplomat with the American Board of Internal Medicine. He's board-certified in internal medicine and board-eligible in gastroenterology.

SNEHAL DESAI

Title: Doctor, Gastroenterology Center of Nevada

Medical education: University of Alberta, Edmonton

The basics: Snehal Desai has been licensed to practice medicine in Nevada since 2004. He's board-certified in gastroenterology and internal medicine, and he's a diplomat with several organizations, including the American Board of Internal Medicine and the Royal College of Physicians and Surgeons, a British group with affiliates in the United States and Canada. He has also volunteered for the Friends of University Hospitals and the University Hospital Foundation at the University of Alberta.

His relationship with Dipak Desai is unknown, though Desai is a common Indian surname.

FRANK FARIS

Title: Doctor, Gastroenterology Center of Nevada

Medical education: Medical College of Wisconsin in Milwaukee

The basics: Frank Faris is board-certified in gastroenterology and internal medicine. He's a member of several trade groups, including the American College of Physicians, the Gastroenterological Association, the American Medical Association, the American College of Gastroenterology and the American Society of Gastroenterology Endoscopy.

He used to lecture at the University of Arizona VA Medical Center in Tucson, Ariz., and he's a diplomat of the National Board of Medical Examiners.

Faris isn't an officer in the Gastroenterology Center of Nevada or the Endoscopy Center of Southern Nevada, but he manages several limited liability companies, including FAF Investments, FAF Holdings, FAF Enterprises and FAF Ogden Valley. He's also president, secretary and treasurer of Frank W. Faris, M.D., Ltd.

CARMELO HERRERO

Title: Doctor, Gastroenterology Center of Nevada

Medical education: Ponce School of Medicine in Ponce, Puerto Rico

The basics: Carmelo Herrero has been a doctor for 17 years. He's director, president, secretary and treasurer of Carmelo Herrero, M.D., A Professional Corp., and general partner of the Herrero Family Limited Partnership. He's also manager of Herrero Properties, which owns a single real estate asset: a $295,000 house on Eaglehelm Place in Henderson.

DAVID MANUEL

Title: Doctor, Gastroenterology Center of Nevada

Medical education: Unknown

The basics: An extensive Web search for David Manuel's professional biography came up empty, except that he's a gastroenterologist in Las Vegas.

ALBERT MASON

Title: Doctor, Gastroenterology Center of Nevada

Medical education: Albert Einstein College of Medicine at Yeshiva University in New York

The basics: Albert Mason has practiced medicine for 30 years, serving as chairman of the department of medicine, the division of gastroenterology and the physicians' aid committee at Fountain Valley Regional Hospital in Fountain Valley, Calif., before moving to Southern Nevada in the late 1990s. As a doctor who's board-certified in internal medicine and gastroenterology, he performs endoscopies and colonoscopies out of the center's Desert Shadow Endoscopy Center on Burnham Avenue. A member of the Nevada State Medical Association and the Clark County Medical Society, Mason is a diplomat with the American Board of Internal Medicine. He's also director, president, secretary and treasurer of Albert T Mason, M.D., A Professional Corp.

RANADEV MUKHERJEE

Title: Doctor, Endoscopy Center of Southern Nevada

Medical education: Calcutta National Medical College, India

The basics: Ranadev Mukherjee is a diplomat with the American Board of Internal Medicine. In addition to serving as director, president, secretary and treasurer of Ranadev Mukherjee, M.D., P.C., he's secretary and treasurer of The East India Co., based in Nevada.

SANJAY NAYYAR

Title: Doctor, Gastroenterology Center of Nevada

Medical Education: Government Medical College, Patiala, India

The basics: Sanjay Nayyar has been a doctor for 16 years. He's board-certified in gastroenterology and internal medicine, and he's a diplomat with the American Board of Internal Medicine. He used to teach in the department of medicine at Rajindra Hospital in Patiala, India. He's a member of the American Gastroenterology Association and the Chicago Society of Gastroenterology.

SHAHID WAHID

Title: Doctor, Gastroenterology Center of Nevada

Medical education: Liaquat Medical College, University of Sindh, Pakistan

The basics: On top of his position as a board-certified physician with the Gastroenterology Center of Nevada, Shahid Wahid is director, president, secretary and treasurer of Shahid Wahid, M.D., P.C. He's a member of the American College of Physicians and the American College of Gastroenterology. He's also a diplomat with the American Board of Internal Medicine.

NICOLAE WEISZ

Title: Doctor, Gastroenterology Center of Nevada

Medical education: Ohio State University College of Medicine

The basics: Nicolae Weisz has also worked as a gastroenterologist in Dallas. Little else is known about him. A Web search for his biography didn't turn up any details.

JENNIFER ROBISON/REVIEW-JOURNAL